This invention relates to a pierce nut installation head used for attaching pierce nuts to sheet metal or other material panels.
Pierce nuts are used in numerous types of equipment. These threaded fastener nuts become attached to a sheet metal panel and are installed in the sheet metal panel through use of a pierce nut installation tool or head. The pierce nut installation head is positioned in a die or fixture having upper and lower platens. A sheet metal panel is positioned between the die platens and when the platens are stroked to move toward one another, the pierce nut installation head positioned within the die cavity dispenses a nut and causes the nut to be installed onto the sheet metal panel. The pierce nut is typically provided in a strip of multiple pierce nuts held together by a retainer, such as a length of wire or other connecting element. Pierce nuts are typically square or rectangular in shape and usually have an internal threaded hole, or an unthreaded hole to accept a thread forming fastener. The pierce nut is forced against the sheet metal panel and the pilot of the pierce nut engages and pierces a hole through the panel in the manner of a blanking operation. The pilot of the pierce nut is then forced into the opening and is retained in connection with the sheet metal panel. Thereafter, the pierce nut provides an attachment point for the article or product being manufactured from the sheet metal panel.
While pierce nut installation heads have been in use for many decades, there is a continuing need to improve these devices. As in the case of any piece of factory tooling or equipment, there is a desire to reduce the number of components comprising the device. In addition to reducing costs, a reduction in components further tends to produce benefits in terms of reliability and serviceability.
During the installation process, the die platens are forced to stroke toward and away from each other. As mentioned previously, the pierce nut installation head is installed within the die cavity. There are advantages to be derived through reducing the stroke distance necessary for the die platens. Such a reduction stroke distance directly translates to a reduction in steel components comprising the die.
In certain prior art pierce nut installation heads, the last nut of a strip of pierce nuts was often not fed and installed onto the sheet metal panel. This produced waste. There is always a desire to reduce the amount of scrap produced in the process of using the pierce nut installation head.
For serviceability reasons, it is desirable to enable the pierce nut installation head to have certain critical components readily detached to allow inspection, clearing, and servicing of the device. Prior designs have often been very inconvenient to allow such disassembly. Accordingly, there is a need in the art to provide a pierce nut installation head having components which can be readily disassembled.
There are a number of sizes of pierce nuts used for various applications. Such pierce nuts vary in terms of their height and perimeter dimensions. Ideally, a pierce nut installation head would be capable of accommodating a range of different pierce nut configurations.
Factory equipment should ideally operate for extended periods without service requirements. Assuring high levels of quality is an aim for every factory operation. In the case of pierce nut installation heads, it is desirable that these devices operate in a trouble-free manner with a long operating lifetime. Moreover, it is important that each nut be properly installed in the sheet metal panel.
The pierce nut installation head of the present invention provides a number of features beyond that in accordance with the prior art and addresses the previously noted needs for such devices. Through the use of unique plunger design and the appropriate selection of the cam surface of the base component, the height of the head can be reduced. Moreover, the die press stroke needed to produce the installation may also be reduced in accordance with the present invention.
Various critical components of the assembly can be readily disassembled through the use of quick release type connections. These allow the device to be easily cleared of jammed nuts or for other inspection or service requirements.
Through the use of a special feed pawl, the device becomes capable of feeding every pierce nut in the strip, including the last nut. Nuts of various dimensions may be used based on the selection of various head design features and parameters, including a novel slide ramp angle.
Reliability is achieved in accordance with the present invention through numerous features. Included are particular features in the nut control system which supports the pierce nuts during the installation process and assures that they are oriented properly with respect to the sheet metal panel.
Additional benefits and advantages of the present invention will become apparent to those skilled in the art to which the present invention relates from the subsequent description of the preferred embodiment and the appended claims, taken in conjunction with the accompanying drawings.